Subscribers to a wireless mobile service, including a global system for mobile communications (GSM) wireless service, may use a general packet radio service (GPRS) for Internet protocol (IP) communications. GPRS facilities may include serving GPRS support nodes (SGSNs) and/or gateway GPRS support nodes (GGSNs). A GSM/GPRS device may connect to a distant IP network by activating a logical channel within the SGSN/GGSN structure, known as a packet data protocol (PDP) “context.”
A client may establish a PDP context by taking affirmative action (similar to that required to establish a dial-up modem connection). The GSM/GPRS network may issue an IP address during activation of the PDP context. A wireless provider may deactivate a client's PDP context when no activity has been sensed for a selected period in order to conserve packet-switched and/or other network resources; and the deactivated client may indicate a state of disconnection from the network.
Information on GSM/GPRS operations is currently available from the Internet at a site of the GSM Association in GSM Association document PRD IR-40, “Guidelines for IP4 Addressing and AS Numbering for GPRS Network Infrastructure and Mobile Terminals, Version 3.1.0: 2001.